This research proposal is focused on three areas of investigation: a. The development of a specific, sensitive and rapid method for taurine analysis in biological tissue. b. The study of the biosynthesis of taurine from hypotaurine in mammalian tissue utilizing a novel radiolabeled form of the precursor. c. The metabolic conversion of taurine to isethionate; the origin of isethionate from other precursors in mammalian tissue and in the squid.